Noncaking dishwashing detergent

ABSTRACT

A METHOD OF MAKING A CHEMICALLY STABLE DOMESTIC DISHWASHING DETERGENT IS DISCLOSED IN WHICH EXCELLENT CLEANING PROPERTIES ARE COMBINED WITH THE ABILITY TO RESIST CAKING BY THE CONTROLLED ADDITION OF, TYPICALLY, ABOUT 2% WATER TO ANHYDROUS SODIUM TRIPOLYPHOSPHATE.

AU 1535 L 6 crates ratent 015cc 3,600,317 Patented Aug. 17, 19713,600,317 NONCAKING DISHWASHING DETERGENT Anthony Ethelbert Lintner, 920Berkshire Ave., Pittsburgh, Pa. 15226 No Drawing. Continuation-impart ofapplication Ser. No. 608,505, Jan. 11, 1967. This application Jan. 27,1970,

Ser. No. 6,319

Int. Cl. Clld 7/56 US. Cl. 252-99 7 Claims ABSTRACT OF THE DISCLOSURE Amethod of making a chemically stable domestic dishwashing detergent isdisclosed in which excellent cleaning properties are combined with theability to resist caking by the controlled addition of, typically, about2% water to anhydrous sodium tripolyphosphate.

RELATED CASES This is a continuation-in-part of my application of thesame title, Ser. No. 608,505, filed Jan. 11, 1967, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to detergents andmethods of making them. More particularly, it relates to alkalinedetergents intended for use in domestic dishwashing machines. Thedetergents of this invention are inhibited 30 against caking.

A common problem in the art of detergents for household dishwashingmachines is that they tend to cake. Detergents which are generally inhydrated form, e.g.,

as an ingredient, tend to cake in the package particularly underelevated and variable temperature conditions and become difficult toremove and place in the dishwasher dispenser. Those which employanhydrous ingredients such as anhydrous sodium tripolyphosphate have agreat afiinity for water so that even a very short exposure torelatively small amount of water or a moist atmosphere at the beginningof the wash cycle may tend to cause cake formation (agglomeration) inthe dispenser. As a result, the dispenser becomes clogged and unable tofunction as it should, while the detergent loses its free flowing andotherwise usually highly soluble characteristics. Compositions whichemploy hydrated ingredients have the additional disadvantages ofmarginal chlorine stability over long periods unde'r variabletemperatures and a lower content of active ingredients per unit ofweight.

Many attempts have been made to overcome the disadvantages of thehydrated and the anhydrous forms, but the problems still persist.

SUMMARY OF THE INVENTION I have found a method of combining more or lessconventional mechanical dishwashing detergent ingredients inconventional mixing equipment by which a product is made havingsurprisingly beneficial properties with respect to hydration.

The more or less conventional ingredients used in my detergentcomposition are as follows:

Percent by weight 7 Preierred Ingredient concentration Range Anhy.sodium tripolyphosphate 53. 955 42-58. Aluminum acetate 1.0 0.5-2. Anhy.sodium metasilicat-e 16.0 12-25. Soda ash or trisodium orthophosphate22. 920 -25. Potassium dichlorisocyauurate 1. 0 0.52.0 Low sudsing,nonionic wetting agent (100 percent active) 4. 0 1-5. 10 Water 1.080 0.75-5. 0.

Dye (optional) 0.005 Up to 0.2. Perfume (optional) 0. 040 Up to 0.4.

The low sudsing nonionic wetting agents are well known in the art. Someof the better known ones are the Pluronic series of ethyleneoxide-propylene oxide block polymers. We prefer to use alkyl arylpolyethers such as Triton CF-lO and amine polyglycol condensates such asTriton CF-32. Any of the low sudsing nonionic wet- 0 ting agentsknown-to be useful in mechanical dishwashing (see McCutcheons Detergentsand Emulsifiers Annual, 1966) may be used. Combinations of such wettingagents are also of use.

A preferred low sudsing nonionic wetting agent is 5 Triton CF-lO," ofthe formula Surfactants which may be employed in the compositions ofthis invention are generally the polyoxyalkylene adducts of hydrophobicbases wherein the oxygen/carbon atom ratio in the oxyalkylene portion ofthe molecule is at least about 0.5. Those compositions which arecondensed with hydrophobic bases to provide a polyoxyalkylene porthosewhich employ sodium tripolyphosphate hexahydrate tion having anOxygen/Carbon atom ratio of at least 0- include ethylene oxide,butadiene dioxide and glycidol and the like. Ethylene oxide, forexample, is condensed with the hydrophobic base in an amount suflicientto impart water solubility and surface active properties to the moleculebeing prepared. The exact amount of ethylene oxide condensed with thehydrophobic base will depend upon the chemical characteristics of thebase employed and is readily apparent to those of ordinary skill in theart relating to the synthesis of oxyalkylene surfactant condensates.

Typical hydrophobic bases which can be condensed with ethylene oxide inorder to prepare nonionic surface active agents include monoandpolyalkyl phenols, polyoxypropylene condensed with a base having fromabout one to six carbon atoms and at least one reactive hydrogen atom,

fatty acids, fatty amines, fatty amides, alkyl mercaptans and fattyalcohols. The hydrocarbon ethers such as the benzyl or lower alkyl etherof the polyoxyethylene surfactant condensates are also advantageouslyemployed in the compositions of the invention.

ene radical. The alkyl substituent on the aromatic nucleus may be octyl,diamyl, polymerized propylene such as propylene tetramer and trimer,isooctyl and nonyl. The benzyl ethers of the polyoxyethylene condensatesof monoalkyl phenols impart good properties to the compositions of theinvention. A typical product corresponds to the formula:

n-Q-ownmmmcmon where R is an alkyl group, and n is from about 5 to 30.

Other suitable water-soluble nonionic surfactants are cogeneric mixturesof conjugated polyoxyalkylene compounds containing in their structure atleast one hydrophobic oxyalkylene chain in which the oxygen/carbon atomratio does not exceed about 0.33 and at least one hydrophilicoxyalkylene chain in which the oxygen/carbon atom ratio is not less thanabout 0.5. Propylene oxide, butylene oxide, amylene oxide and styreneoxide are illustrative of oxyalkylene compounds having an oxygen/ carbonatom ratio not exceeding about 0.33 while ethylene oxide, butadienedioxide and glycidol, as previously pointed out are illustrative ofoxyalkylene compounds having an oxygen/carbon atom ratio of at leastabout 0.5. Although the hydrophobic chain has an oxygen/ carbon atomratio not exceeding about 0.33, it is often advantageous to include inthis chain a small amount of ethylene oxide, that is, up to aboutfifteen weight percent, and likewise in the hydrophilic chain which hasan oxygen/ carbon atom ratio not less than about 0.5, it is oftenadvantageous to include a small amount of propylene oxide or butyleneoxide, that is, up to about fifteen weight percent, and theoxygen/carbon atom ratios described herein and in the claims are notintended to preclude such mixtures.

Among the conjugated polyoxyalkylene compounds which can be used in thecompositions of the invention are those which correspond to the formula:

wherein Y is the residue of an organic compound having from about one tosix carbon atoms and one reactive hydrogen atom, 11 has an average valueof at least about 6.4 as determined by hydroxyl number and m has a valuesuch that the oxyethylene portion constitutes about to 90 weight percentof the molecule. Most of the surface active agents are more particularlydescribed in US. Pat. No. 2,677,700. They are sold under the trademarkPluronic.

Other conjugated polyoxyalkylene surface active agents which are mostadvantageously used in the compositions of the invention correspond tothe formula:

wherein Y is the residue of an organic compound having from about two tosix carbon atoms and containing x reactive hydrogen atoms in which x hasa value of at least about two, n has a value such that the molecularweight of the polyoxypropylene hydrophobic base is at least about 900and m has a value such that the oxyethylene content of the molecule isfrom about 10 to 90 weight percent. Compounds falling within the scopeof the definition for Y include, for example, propylene glycol,glycerine, pentaerythritol, trimethylolpropane, ethylenediamine,triethylenetetramine, triisopropanolamine and butylamine. Where Y isethylenediamine, the compounds may be represented by the formula:

H( :H4o)y( 3 6O):

N-Cm-CH N H(CIH4O)Y(C3HGO); 3H6Olx(CgH4O);H

wherein x and y are integers. Products of this type are sold under thetrademark Tetronic. As already noted, the oxypropylene chainsoptionally, but advantageously, contain small amounts of ethylene oxideand the oxyethylene chains also optionally, but advantageously, containsmall amounts of alkylene oxides having an oxygen/ carbon atom ratio ofnot more than about 0.33 such as propylene oxide and butylene oxide.Most of these compounds are more particularly described in US. Pat. Nos.2,674,619 and 2,979,528.

Other suitable polyoxyethylene nonionic surface active agents are theethylene oxide adducts of higher aliphatic alcohols having from about 8to 22 carbon atoms in the aliphatic portion, and about 3 to 30 ethenoxyunits in the oxyethylene portion. Typical products are blends of linearfatty alcohols containing an even number of carbon atoms condensed withabout three to nineteen moles of ethylene oxide.

Other suitable nonionic surface active agents are the propylene oxideadducts of condensates of ethylene oxide and higher aliphatic alcoholshaving from about 8 to 22 carbon atoms in the aliphatic portion. Variousratios of ethylene oxide and propylene oxide may be used.

Other suitable nonionic surfactants are the products prepared bycondensing a mixture of ethylene oxide and propylene oxide withaliphatic alcohols having from about 8 to 22 carbon atoms in thealiphatic portion of the alcohol. Various ratios of oxides may beemployed.

Other suitable surface active agents are the polyoxyalkylene surfaceactive agents having heteric polyoxyethylene solubilizing chains. Thesepolyoxyalkylene compounds conform to the following generic formula:

wherein Y is the nucleus of an organic reactive hydrogen compoundcontaining x reactive hydrogen atoms and having up to six, inclusive,carbon atoms, x is an integer, P is a hydrophobic polyoxyalkylene chainhaving an oxygen/carbon atom ratio of not more than 0.40, the molecularweight of P and the value of at being such that the molecule, excludingE, has a molecular weight of at least about 400 to 900 and up to about25,000, and E is a hydrophilic heteric polyoxyalkylene chain which (1)contains oxyethylene groups and at least five percent by weight ofhigher molecular weight oxyalkylene groups having at least three carbonatoms in their structure, and (2) has an average oxygen/carbon atomratio of greater than 0.40, E being present in the composition to theextent that it constitutes from 5 to 90 weight percent of the totalcomposition. These compositions are more particularly described in US.Pat. No. 3,101,374. Mixtures of these compositions and fatty acidphosphates may also be used.

Any of the above surfactants may be referred to as low sudsing nonionicwetting agents.

An example of a suitable dye is Lanasyn Brilliant Green B.L., having theformula:

NMIMS Any of the common commercial detergent dyes and perfumes may beused. Pine fragrance oil is an acceptable perfume.

The sodium tripolyphosphate, which is anhydrous, should preferably havea particle size such that at least by weight of the particles passthrough a U.S. screen number 20 and only about 5% will pass through aUS. screen number 80. The amount of water used is always less than 10%of the weight of anhydrous sodium tripolyphosphate and preferablycalculated to be about 7% of it. A preferred amount of the sodiumtripolyphosphate is 54% by weight. The hydration step is carried out ina particular manner. The low sudsing nonionic wetting agents (typicallyTriton CF-32 or Triton CF-l O) are dissolved along with the optional dyeand perfume in the water, which is then sprayed onto the sodiumtripolyphosphate with continuous and simultaneous mixing or agitation.The surfaces of the granules of the sodium tripoly= phosphate are thusmade immediately and evenly wet by the small quantity of watercontaining the wetting agents, dye and perfume. In this manner, asurface layer of sodium tripolyphosphate hexahydrate is formed on thegranules of sodium tripolyphosphate, while the sodium tripolyphosphatein the interior of the granule remains in.

the anhydrous form. As the aqueous solution is added. the added waterbecomes part of the sodium tripolyphosphate molecule. The otheringredients are then added to the mixture and a free flowing,non-sticking. noncaking chemically stable product is formed. When thedetergent is placed in the dishwasher dispenser, its major surfacecomponent, hydrated sodium tripolyphosphate, is no longer reactive towater because it is already hydrated and therefore does not readilyabsorb moisture which prematurely enters the dispenser. The majormechanism by which caking occurs is thus averted; e.g. formation ofhydrate bridges is retarded.

Laboratory and field tests have shown that the incidence of caking of mynew partially hydrated product is far less than that with an anhydrousproduct of similar composition.

I do not intend to be bound by the above specific examples andillustrations of my invention. It may be otherwise practiced within thescope of the following claims.

I claim:

1. Method of making a noncaking mechanical dishwashing compositioncomprising (a) preparing a premix consisting essentially of, in percentby weight, about 15% low sudsing nonionic wetting agent, about 0.755.0%water, and small amounts of dye and perfume, (b) spraying the premixonto about 42-58% anhydrous sodium tripolyphosphate having a particlesize distribution such that no more than about 15% is retained on a US.screen number 20 and no more than about 5% is passed through a U.S.screen number 80, while agitating the sodium tripolyphosphate wherebythe surface of the sodium tripolyphosphate particles is hydrated, and(c) mixing the hydrated sodium tripolyphosphate with about 0.52%aluminum acetate, about 12-25% sodium metasilicate anhydrous, about20-25% of a compound of the group consisting of soda ash and trisodiumorthophosphate and about 0.5-2.0% potassium dichloroisocyanurate,whereby a free flowing, noncaking product is obtained.

2. Composition made by the process of claim 1.

3. Method of claim 1 in which about 1.0% potassium dichloroisocyanurateis used.

4. Method of claim 1 in which about 16.0% anhydrous sodium metasilicateis used.

5. Method of claim 1 in which the low sudsing nonionic wetting agent isof the group consisting of ethylene oxide-propylene oxide block polymersand amine polyglycol condensates.

6. Method of claim 1 in which the water used is about 7% by weight ofthe anhydrous sodium tripolyphosphate.

7. Method of making a noncaking mechanical dishwashing compositioncomprising (a) preparing a premix consisting essentially of, by weight,about 4% low sudsing nonionic wetting agent, about 1.08% water, andsmall amounts of dye and perfume, (b) spraying the premix onto about 54%anhydrous sodium tripolyphosphate having a particle size distributionsuch that no more than about 15% is retained on a US. screen number 20and no more than about 5% is passed through a US. screen number 80,While agitating the sodium tripolyphosphate whereby the surface of thesodium tripolyphosphate particles is hydrated, and (c) mixing thehydrated sodium tripolyphosphate with about 0.52% aluminum acetate,about 12-25% sodium metasilicate anhydrous, about 20- 25% soda ash ortrisodium phosphate, and about 0.5- 20% potassium dichloroisocyanurate,whereby a free flowing, noncaking product is obtained.

References Cited UNITED STATES PATENTS 3,306,808 2/1967 Oberle 282-993,350,318 10/1967 Green 252-99X 3,359,207 12/1967 ,Kaneko et al. 2S2993,361,675 1/1968 Fuchs et al 2S299 MAYER WEINBLATT, Primary ExaminerUNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,500,317 Dated August 17, 1971 Anthony Ethelbert Lintner Inventor(s) Itis certified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

In the heading to the printed specification, after line 4, insertassignor to Calgon Corporation, Pittsburgh, Pa.

Signed and sealed this 25th day of July 1972.

(SEAL) Attest:

EDWARD M. FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents RM PC4050 (L691 USCOMM-DC 60376-F'69 n U S GQVERNMENTPRH'TING OFFICE: I! -J-Jll

